(a). Field of the Invention
The present invention relates in general to a system and method for network connection detection, and more particularly to a system and method that operate in a link layer to detect connection status of a local area network (LAN) by transceiving control frames.
(b). Description of the Prior Arts
For network users, especially network administrators, it is necessary to confirm that network devices operate normally and physical network connection between them is maintained. Loopback test is commonly used to determine whether hardware of network devices, such as network interface card (NIC) or network switch operate normally. The loopback test for the media access control (MAC) layer of the link layer (Layer 2) is performed by configuring registers of the network devices by software drivers and transmitting signals from the Transmitter to the Receiver. However, when detecting whether the connection between a NIC and a hub or Layer 2 switch is maintained, only t he software program (e.g. common used Ping program) is used to send IP packets of the Network layer (Layer 3) to some remote host for connection detection. If no response is received after sending the IP packets, there are several possible causes: network cable or the connected Layer 2 switch may go wrong, one or some routers of the network are disable to forward packets, the remote host does not power up, etc. However, more information is not offered to determine what is the specific cause for the network disconnection.
In view of this, the present invention provides a system and method for detecting connection status between two network devices (e.g. a NIC and a Layer 2 switch, or two NICs) within the network by transceiving Layer 2 packets, i.e. request frames and reply frames, thereby facilitating to find the status of network disconnection.